Apparatus for settling coatings



I a If Dec. 6, 1955 J. B. LINDSAY 2,725,643

APPARATUS FOR SETTLING COATINGS Original Filed Feb. 24, 1949 9Sheets-Sheet 1 wn I" INVENTOR JAMES B- LINDSAY ATTO EY Dec, 6, 1955 J.B. LINDSAY 2,725,641

APPARATUS FOR SETTLING COATINGS Original Filed Feb. 24, 1949 9Sheets-Sheet 2 INVENTOR JAMES B. LINDSAY NEY ea. 6, 1955 J, LlNDSAY2,725,641

' APPARATUS FOR SETTLING COATINGS Original Filed Feb. 24, 1949 9Sheets-Sheet 3 8 INVENTOR JAMES B. LINDSAY Dec. 6, 1955 J. B. LINDSAY2,725,641

APPARATUS FOR SETTLING COATINGS Original Filed Feb. 24, 1949 9Sheets-Sheet 5 INVENTOR JAMES B- LINDSAY Dec. 6, 1955 J. B. LINDSAY2,725,641

APPARATUS FOR SETTLING commas Original Filed Feb, 24, 1949 9Sheets-Sheet 6 INVENTOR JAMES B. LINDSAY q RNEY 6, 1955 J. a. LINDSAYAPPARATUS FOR SETTLING commas 9 Sheets-Sheet 7 Original Filed Feb. 24,1949 Y AM Rs Y OD E m N E v m w Dem 6, 1955 J. B. LINDSAY APPARATUS FORSETTLING COATINGS 9 Sheets-Sheet 8 Original Filed Feb. 24, 1949 R M E mm m m5 m Q a Q m N m& K w A B J W vmwwm $2M I I .QQN %%N jhQsw 3 us: 53%

Dec. 6, 1955 J. B. LINDSAY APPARATUS FOR SETTLING commas 9 Sheets-Sheet9 Original Filed Feb. 24, 1949 a QM MR wk NR Mk wR NR I l l I I l I Jmxmi INVENTOR JAMES B. LINDSAY United States Patent- Y 2,725, 64!APPARATUS. FOR .sETrLING .CQATINGS IamesB. Lindsay, "Millburn, 1.1.,assignor to Radio .Corjporation of America, e1 corporation of Delaware on l appliCatiOnFebruary ZQ, 1949,"serin -No..7,8,077. Divided land thisapplication v,(lctober 20, 1,951, Serial TNO.'252,367

This invention relates to the formation of coatings r-and=-rnoreparticl1larly to an apparatus for 'facilitatingthe production of suchcoatings which are applied in the form of 'a mechanical-mixture orsuspension and then allowed -:to settle out upon the surface to becoated.

This is a division of my application Serial No. 78,077 filed February24, 1949, now l-atent 2,646,769, and as- .signed'to'the same assignee asthe present application.

7 One example of suchcoatings is the'luminescent screen on the faceor-end of acathode-raytube-envelope which, insofar as I am familiartherewith, were applied by a socalled 'tilt table" apparatus prior tothe advent of'the method and apparatus disclosed-in 'the =co;pend-ingapplication of J. Kent Burton, Serial Number 67,964, "filed December 29,1948, now Patent 2,646,773 in accordance :with which objectshavingsurfaces onto which particles suspended in :solution are to-be applied,are moved continuously and at acon'stant speed through various positionssuch as dispensing, settling, decanting, washing and drying.

'Snch screens usually consist of several "ingredients which must bemaintained separate *until they'are-intermingled 'atsthe time thecoating is'to beforrned and may include a concentrate of a phosphor, anelectrolyte, a binder and water. When these ingredients are broughttogether in the proper' proportions aluminescent screen consisting ofa'binder and a phosphor is formed'from which excess liquid 'isrcmovedand the screen dried. Not only should the ingredients be added inaccurately measured quantities .but the order in which they are addedhas also been found to affect the quality of the screen formed.Furthermore the nature of these-ingredient-s is such that if they comeinto contact with parts of the object other than that "intended toreceive the coating, suc'h parts receive an objectionable film.

H-eretofore such objects have been individually "charged with coatingingredients necessitating the pres- -ence of an operator *to performthis function and -who had to exercise constant care to :avoid smearinginner or outer surfaces o'f the tube envelope-with coating ingre--dients. Then the screen forming particles were settled, care beingtaken to avoid mechanicals'hocks or vibration which would disturb theeven settling of the particles and hence the uniform density ofthescreen.

Thus, a principal object of my invention is to-provide an "apparatus tofacilitate the application of screens or coatings formed by the settlingout "of particles "from mechanical solution onto-the surface-"to 'becoated thereby.

Another object of my invention *is the provision of such apparatus whichis fully automatic in operation.

A further object is to provide such apparatus which operatessubstantially free from vibration and which produces substantiallyuniform coatings"freeTrombletnishes.

"Yet another object is the provision of means which facilitate -.thcinsertion and removal ofobjects to be coated'by'the apparatus.

,A-still further objectiis-"theprovision of-such apparatus 2 'tirel ythe possibility that relatively fragile objects will become chipped,cracked or broken.

Other objects will appear as the nature of my invention is morefully-understood from the following description taken -in conjunctionwith the accompanying drawings wherein like parts are identified byidentical numerals in the several views.

.'In the accompanying drawings, wherein is shown, by way of --illustration, one of the embodiments which the present invention may take:

Figure lg-is aside elevational view on a reduced scale of an apparatusconstructed in accordance with my invention;

Figure 2 is a fragmentary perspective view of the left end of theapparatus shown in Figure *1;

Figure 3 is a sectional -view on an enlarged scale of the envelopeholder with the carriage therefor shown in elevation; i v

Figure :4 is a plan view of a modified holder;

Figure 5 is a schematic view illustrating another embodiment of themeans for guiding the carriages around :the ends of the conveyor;

Figure 6 is a front elevational view of the dispenser;

Figure '7 is a plan view of the dispenser;

Figure 8 is a sectional view on an enlarged scale :through the line 8-8of Figure 6;

Figure .9'gis -a View similar to Figure "8 with the parts shown inposition prior to actuation;

Figure 1-0 is a sectional view through the line 10-10 'nffigure 9 withthe discharge tubes shownopen;

1 -.Fignre 1 1 is :asectional :view through the line '11 '11 ofFigure-.9;

Figure 12 is a sectional view on an enlarged scale through-theline12-'12 of Figure 9;

Figure tl'3 iis a side elevational 'view partially in section (if therinse and dry apparatus shown in Figure l;

Figure '14 is a sectional view through the line '14-14 of Figure I;

I'Figure wis-a view along the'line 15-15 of Figure '13 in the directionindicated;

T'Fignre "116 .is :a schematic '-view of the hydraulic system forcontrolling the dispenser elevating mechanism;

:Eigure :17' 'is :a schematicwiring diagram of the appa- :ratus;:and

Figure -1-8 :is a sectional view on through ".the line181'8 of Figure'13.

Referring first 'to Figure 1, it will 'be seen that my apparatus mayinclude an endless belt type conveyor, :21 :dispenscr 2'1, rinseapparatus 22 and drying apparatus 23.. "Objects such as cathode-ray tubeenvelopes when loaded .on aconstantlys'moving conveyor 20-at station A,*aretcarried-throug-h dispensing station B where they automaticallyreceive a charge of coating or screen forming ingredients from=disepenser21. The envelopes continue .=movement substantiallyundisturbed 'for a time long :enoughto :permit even settling-of thecoating. On arrivf'ing in position C the coating forming particles "havesettled :and between 'C-and D excess liquid is. poured ofi. .Thepouringsoff of excess liquid is carried out in an extremely slow andsteady manner to *avoid disturbance of the .screen orcoating by theliquid. Then between E and G the coatings are set. Thus, at E theenvelope necjks :may be rinsed While between -"F and G the screens orcoatings :may be air dried. -On returning to A, the envelopesWith-SCX'CEHS formed thereon are removed.

an enlarged scale Thetconveyor Referring nowto' Figures 1-6 in detail,conveyor20 is seen to "have a main supporting frame indicated genorally:at ":24 having :suitalaly interconnected horizontal and verticalmembers 25, 26 as required. Supported by thezzftamezand ratteach end:thereof :are rotatably mounted shafts 27, 28. Shaft 27 is mounted ateach of its ends in bushings 29 (only one of which being shown)adjustably movable in housings 30 by means adjusting screws and springs.A pair of idler sprockets 31 are mounted to rotate with shaft 27, oneadjacent each end thereof. A pair of drive sprockets 32, one inalinement. with each of idler sprockets 31 are mounted to rotate withdrive shaft 28 on opposite end. On a separate support 33 which is notconnected in any manner to frame 24 is a motor 34 connected to a sourceof electrical power supply and to a reduction gear 35 which in turn isconnected through a system of resilient belts 36 and pulleys to one endof shaft 37. On the other end of shaft 37 is a worm gear 38 which mesheswith a suitable gear 39 keyed to shaft 28. It is to be noted that theonly connection between the main conveyor and the motor platform is thebelts 36 which serve to prevent the transmission of undesirablevibration from the motor to the conveyor.

Also supported at each end of frame 24 are four substantiallysemi-circular guide plates 40, one such plate being disposed outwardlyof and concentric with each of the two idler sprockets 31 and the twodrive sprockets 32. As most clearly shown in Figure 2, plates 40 may besuitably connected to each bushing 41 in which the shaft 28 is rotatablymounted and to bushings 29 at the other end of conveyor 20. A channeledarcuate guide 42 is connected adjacent to the periphery of each guideplate 40 and has an outside track 43 and an inside track 44 formingarcuate channel 45. Each outside track 43 may be provided with a facingor layer 43a of resilient material such as rubber or the like. v

Two roller link endless chains 46, one stretched over sprockets, form anupper course 20a and a lower course 20b. Rails 47 are disposed one oneach side'of upper course 20a and lower course 2% and extend parallel tothe same. Thus, there are four rails '47, the upper pair of which areclearly shown in Figure 6 while each rail of the lower pair -is belowone of the upper rails and in alinement therewith. Rails 47 may beconnected to horizontal frame members 26 along their lengthand'supported thereby in spaced relation with respect to" the chains. 3v

A plurality of carriages indicated generally at 48, Figures 2 and 3, arecarried by the conveyor, interconnecting the two chains-and supported bythe rails 47, while those carriages passing around the ends of theconveyor from and in mesh with each set of alined drive and idler Hrelation on the outer orupper surface of cross pieces 49 (looking in thedirection of Fig. 3) by means of bolts 59 or the like. As is apparent inFigure 6 each carriage may carry three such holders 58 though theapparatus may be designed for more or less as desired. Thus, in thepresent instance there are three lines of holders which extendlongitudinally of the conveyor while the rows which extend transverselyof the conveyor each consist of three'holders and there are as many suchrows as there are carriages. Each holder 58 includes a receiverv havinga base 60 and an upstanding annular wall 61. Wall 61 has an annularrecess sor channel formed therein adjacent itsupperor open end in whichis positionedan endless inflatable tube 62 substantially D-shaped incross-section. I have'found that such a D-shaped tube permits the. readyinsertion and withdrawal of an object such as cathode-ray tube envelope63 when deflated and yet securely retains the envelopes in the holderswhen inflated. An air valve is connected to tube 62 by means of stem 64which passes through an opening in wall 61.

Also connected to each cross-piece 49 and depending therefrom (Fig. 3)is an actuator bar 65 which as will be seen operates various switches asit is carried around the path described by the carriages.

As is apparent in Figure 1, dispenser 21 ,is located over and adjacentone end of conveyor 20. In alinement with theconveyor and spaced fromthe other end thereof is a splash shield 66 (Fig. 2) having a trough 66adisposed to receive liquid collected by the shield and conduct the sameto a container or sewer (not shown). Carriages 48 are of such dimensionsthat rolls 51, 52 on each side thereof arein registration with andtravel on the corresponding rails of either the upper or lower courseofthe conveyor. As each carriage approaches the left hand end ofupperrails 47 each guide roll 57 engages one of the arcuate outer tracks 43on guide 42 The curvature of track 43 is such that as guide roll 57travels along the same rolls 51, 52 are maintained in contact withinside track 44 since the carriages are free the. upper to thelower-course or from the lower to the upper course are supported by therespective guides 42. Each carriage includes a cross piece 49 which isconnected at each of its ends to the upper portions of side plates ortrucks 50. Each truck 50 is recessed at one end thereof to receive aleading-roll 51 and -at the other end to receive a trailing roll 52.Trailing rolls 52 are rotatably mounted on pins 53 while leading rolls51 are rotatably mounted on a stub shaft 54a at each end of a connectingrod 54 which extends between the side plates or trucks 50 and thusserves to interconnect the centers of leading rolls 51 of the carriage.At the point where connecting rod 54 passes each chain it is connectedthereto by flanges 55 and bolts 56 or the like. It is to be understoodthat while connecting rod 54 is rigidly connected to the chains, sideplates or trucks 50 are free to rotate about stub shafts 54a and aretherefore rotatable with respect to the chains the purpose of which willbe more fully pointed out hereinbelow. Rotatably mounted on the outersurface of each side plate or truck 50 is a guide roll 57 of suchdiameter and length as to extend beyond-rails 47 and enter channel 45and pass therethrough in rolling engagement with the corresponding outertracks 43 as the carriages pass around the sprockets from the uppercourse to the lower course and also at the opposite end when they passaround the idler sprockets from the lower course to the upper course.

Each carriage 48 carries holders 58 connected in spaced to rock aboutthe connecting rods 54. When the carriages complete the circuit ofguides 42, 180 around the drive sprockets, their rolls have just beenpositioned on the lower rails and thus as the rolls leave the insidetrack 44 they, are already rolling freely on said lower rails. When thecarriages arrive at the right hand end of the lower course the guiderolls 57 are once again similarly engaged by the arcuate guides 40associated with idler sprockets .31 and the carriages are guided andsupported around the idler sprockets as previously. pointed out inconnection with the drive sprocket end of the conveyor.

During operation the conveyor is constantly driven at a uniform speed bymotor 34. The distance between the centers ofshafts 27 and 28 isselected so that the carriages may traverse the path described by theconveyor at a relatively slow rate, approximately four to six inches per.minute being satisfactory when luminescent screens are being settled.Another factor which must be considered is that after the envelopes arecarried past the dispenser 21 suflicient time must remain for thecoating to settle out of solution onto the face of the envelopes beforethey are carried around the drive sprockets to the lower course. Thus,the maximum permissible speed will be determined by the length oftheconveyor and the time required for settling.- Since suchcoatings aresensitive to vibration it is necessary to maintain the rate at which theconveyor travels relatively slow.

The dispenser Envelopes 63, Fig. l, loaded onto the carriage in posi*tion A are carried up over the idler sprockets through position B whereas the envelopes continue in motion the dispenser is actuated to moveinto' dispensing or operating position and deliver to each envelope acharge of coating ingredients. Referring now to Figures 1; 612, it isseen thatdispenser 21 is supported on a platform67 spaced vzahoveconveyor 20. As is apparent in Figure 6, platform 367 hasan opening-68:and supports on one side of this opening a tubular column 69 on whichis mounted a :vertically movable ;slide 70. vAlso positioned on platform.67 and adjacent tubular column 69 is an air cylinder 71 which isvertically positioned and has a piston rod 72 rigidly connected to ashelf 70a integral with or connected to slide 70. .Also connected to the.piston rod 72 of the air cylinder andopposed thereto is a piston rod 73of a hydraulic cylinder 74 connected to tubular column 69 at .theupp'erends thereof. Collar 75 is rigidly mounted on tubular column 69 adjacentthe lower end of hydraulic cylinder 74. .?Hydraulic control valves 76,77 are mounted :one on each :side on collar '75. Each control valve .hasa :stem 78, 79 carrying a roll 80, 81,.respectively. Spaced from each ofthe rolls 80, 81 is a backing roll 82, 83 iadjustably connected to androtatable on collar 75. Connected to shelf 70a intermediate the piston72 and "slide .70 are .two upstanding cam rods 84, 85. As is most:clearly :shown :in Figures 6 and 7, cam rod 84 passes between valve;stem roll-80 and backing roll 82; these rolls being in rollingengagement therewith while cam :rod 85 extends between roll 81andbacking roll 83} The :cam rods being pivotally connected to shelf 70a,their Llaterally displacement is controlled by backing'rolls 82, 83.Thus, it is seen that the backing rolls together with cam rods 84, 85control the travel of valve stems 78, 79.

cylinder 71 has connected thereto adjacent each "of :its ends air lines86, 87 connected to a source of air \pressure and an exhaust line (notshown) through a solenoid actuated control valve 76. Hydraulic cylinder74 is connected .at .each of .its ends to a closed hydraulic -fiuidsystem which'acts to control the operation 'of air :cylinder '71. Thelower end ofhydraulic cylinder 74 is,

.as is schematically shown in Figure 16, connected to '.tub.e":87leading to controlvalve 76. The other side of control valve 76 has :atube 88 open to accumulator 89 and which is connected to one side ofcontrol valve 77. The other side 'of the control valve '77 is connectedto the upper end of hydraulic cylinder 74 by a tube 90. Since :theamount of .hydraulic fluid displaced from cylinder 74 varies 'as pistonrod 73 enters and leaves the same, the accumulator is placed in the lineto provide :for this. The system is maintained completely full at alltimes by a suitablefiller at 88a, Fig. 16. .Also the system iiswmaintained at some predetermined pressure to insure proper control.The desirable pressure will depend upon the load involved and is readilyascertainable.

;Rigidly connected to the slide 70 adjacent to the lower :end :thereofis an elevator frame 91 adapted to pass =;through the opening 68 inplatform 67. Opposite tubular column 69 and positioned to the other sideof elevator 1-frame91 is an upstanding supporting column 92 which isalso carried by platform 67. Connected to the upper and lower ends ofsupporting column 92 by means of I acollars 93, 94 are verticallypositioned bar rails 95, '96. .Rails 95, '96 terminate at their upperends in collar 93 :which supports an'upwardly presented extension 97 onwhich is rotatably mounted pulley 98. A "cable 99, :threaded throughpulley 98, is connected at one end to elevator frame 91 as indicated at100 while its other :end is connected at 101 to a compensating Weight102 vertically slidable in the "bore of supporting column 92. Positionedon a side of elevator frame 91 are two horizontal 'pins 104, .105 whichextend into the passageway formed by bar rails 95, 96. IPins 104, 105are vertically and horizontally displaced with respect to one anotherand carry rotatably mounted at their ends rolls '106 and Y107,respectively. As is most clearly shown in Figure 7, roll 106 .is inengagement with bar rail 95 while'roll 107 is in engagement with rail 96thereby eliminating the possibility of lateral sway as elevator frame91travels up anddown.

.Switches S and S6 may be mounted adjacent to one another supported byacollar 169 which is slidable on n6 supporting column 92 and-whichmaybeclamped there .on in any desired position. .Both :of these switchesare maintainedclosed by the elevator frame 91 when it is in its startingor raised position. .Switch S5 is a triple pole switch and as indicatedin Figure .17 is connected ion one side to the source ofelectricalcurrent supply while on the other side it .is connected in series witheach .of

V the switches S3 as will be more fully'described below.

Three'similar dispensing .units 108,, 109.and 110 are disposed onelevating frame 91 and carried thereby. 1n .asmuch as the constructionand operation of each of these dispensing units are identical in everyrespect, I :shall point out in detail the specific construction andoperation of only one such dispensing 'unit and for the sake .tofclarity and'brevity, I have indicated corresponding parts of eachdispensing unit with identical reference char-ac ters in the drawings.Dispenser 108 includes a liquid holding tank having three walled oficompartments 111,, 112 and 113, each being adapted to store a quantityof one of the ingredients to be discharged from the :dispenser unit. Asindicated, compartment 111 is provided with-an agitator 114 though anyor all of the compartments maybe equipped with agitators as desired.Each compartment has an outlet opening prov-ided witha valve seat 115while a valve stem 116 depends from the cover of each compartment andcarries a valve 117 which rests on valve seat 115 in sealing engagementtherewith. At their upper ends valve 'stems 116. areeach connectedfto asolenoid 118. The discharge openings from the three compartments arelocated adjacent to one another and each has a "length .of resilienttubing 11 9 in registration vtherewith and depending therefrom. .Spacedintermediate the three tubes 119 and -depending-from elevator .frame .91is a rail .120 having three slideways 121, 122 and 123. Each of theslideways is presented toward one .ofthe tubes 119. As'mostclearlyshown-in L'Figure 1O, tubes 119 may be conveniently-spaced apartwith respect to the center of rail 120. Solenoid actuated and airpressure operated clamps 124, 125 and 126 are slidably mountedrespectively on slideways :121, 122 :and .123 .and each encircles one ofthe tubes 1'19. .Eachsfsolenoid actuated clamp ,may be positioned in anydesired location along the length of its slideway by 'meansrof .alocking screw 127, and when deenergized 'pinch their respectiveresilient tubes '119 so as to collapse the walls thereof and make aliquid tight seal. To .fac'ilitateithe .location of each of the solenoidactuated :clarnps in its proper position, a graduated scale maybe placedalong .rail .120 as indicated at 128. I t:should be understood thatvalve stems 116 as well as clamps "124, 125 and .126 are actuated bysolenoids and operated "by air pressure delivered from air cylinders notshown. The lower ends of tubes .119 are open to the atmosphere and:ovei-hang .a funnel 128, the construction of which will now :pointedout.

Funnel or mixer 128, Figures 8, '39 and 111 (of vhich there are three,one for each of the dispenser-units) :is substantially rectangular incross sectionhaving a depending spout 128a and carried by ;a cradle 12910 which it may he rigidly connected by .means of straps 130 or thelike. Cradle 129 is provided with four wheels .131 which run on theupper :surfaces of two parallel tubular rails 132, the ends of which aresupported by elevator frame 91 and which extend :in a dimetionparallelthe upper course of conveyor 20. Cradle .129 may be-provided with twoauxiliary wheels-i133, tone .to run along and engage the under*JSlIlfflCB of each "(if the tubular rails "132. Cradle 129 is providedwith "a depending skirt portion v134 which substantially encircles thelower portion of funnel "128. A pair of -bushings :135 one of each sideof skirt portion 134 are "mounted intermediate the ends thereof and toreceive the pivots .136 of a U.shaped yoke 137 which in Figure "11eittends around and below 'one end of funnel 128. "The .arms of the yokeextend somewhat beyond and above pivots 136'and have transverse bores138 extending therethrough adjacent the ends thereof. As will beapparent, bores 138 are vertically disposed in one position of yoke 137and tilted in another. A pair of rods 139 are-slidable in bores 138 anddepend from the arms of yoke 137. Collars 140 are adjustably connectedadjacent the upper end of each of the rods 139 and abut against theupper surface of yoke 137 and thereby serve to support rods 139 in theirlowermost position. A second ring-shaped collar 141 encircles each ofthe rods 139 intermediate its ends and may be clamped in any desiredposition along the length thereof. As is clearly apparent, collars 141are positioned below yoke 137 while collars 140 are positioned above thesame. Also encircling each of the rods 139 is a sliding bearing 142 eachof which is vertically slidable along its respective rod intermediatethe lower end of the rod and collar 141. A stop nut 143 or the like isthreaded on the lower end'of each rod 139 and serves to retain slidingbearings 142 when the same are in their lowermost position. An elongatedplatform 144 is supported and connected at each of its ends by one ofthe sliding bearings 142'and has suitably positioned apertures throughwhich rods 139 extend. Depending from platform 144 is a trigger bar 145the center of which is substantially in alignment with the axis offunnel spout 128a and the axis of the neck of an advancing envelope 63.The vertical'length of trigger bar 145 (Figure 9) is such that itdepends sufficiently far below platform 144 and the lower end of funnelspout 128a as to be engaged by the neck of an advancing envelope 63 whenthe dispenser 21'is in its raisedposition or removed from operatingposition. Extending from the edge of platform 144 (Figure 12) which ispresented toward funnel spout 128a is a U-shaped lip 146. The centerline of lip 146 is also in registration with the axis of spout 128a andits arms are so spaced apart as to lie one on each side of and adjacentto spout 128a.

An adjustable set screw 147 is centrally mounted on yoke 137 and engagesa stop 148 carried by cradle 129 so as to control the maximum rotationout of horizontal position of yoke 137 about its pivots 136. Thus theamplitude of the arc described by rods 139, platform 144 and trigger bar145 is a function of the distance from the end of stop screw 147 to stop148 when yoke 137 lies in a horizontal position.

A drip collector may be provided to catch drippings from spout 128aafter it has been raised. Supported by skirt 134 of cradle 129 andextending transversely below funnel 128 (Figure 11) are a pair of rods149,

150. Rods 149, 150 are horizontally disposed and are connected at eachof their ends to skirt 134. Depend- .ing from rod 149 and pivotallyconnected thereto is a pair of parallel levers 151 (Figures 8, 9). Asimilar pair of parallel levers 152 are pivotally connected to anddepend from rod 150. Levers 151 and 152 form a parallel system and arepivotally connected at their lower ends-to the arms 153 of a drip pan154. Drip pan 154 has an inclined floor which serves to direct anyliquid collected by drip pan 154 toward an opening 155 formed thereinand which is connected to a flexible waste pipe 156. A motor 157 iscarried by skirt 134 of cradle 129 and has a crank 158. interconnectingcrank 158 and one of the levers 151 which supports drip pan 154 is alink 159 having a sleeve or collar 160 connected to one end thereof andwhich engages said lever 151. Motor 157. may .-be equipped with aone-half turn clutch so that when energized crank 158 turns 180 and thenstops. A switch:- S1 is carried by skirt 134 and is so positioned belowyoke 137 as to be thrown by the yoke when the same moves from a tiltedposition to the horizontal position; Switch S1 may also serve to biasthe yoke to its tilted position or separate biasing means in the form of-a coil spring or the like may be used. Switch S2 is also carried byskirt 134 and depends therefrom so as to be closed by platform 144 afterit has traveled upwardly along the rods 139 and when it'reaches itsuppermost position. I

As pointed out, funnel 128 carried by cradle 129 is free to travel ontubular rails 132. In its starting or right-hand position (Figure 9)cradle 129 is in engagement with a switch S3 which it maintains open.Switch S3 is connected to elevator frame 91 and is positionedintermediate tubular rails 132. Another motor 161 is mounted on elevatorframe 91 adjacent the starting or right-hand position of funnel 128 anddrives a pulley 162 which winds a cable 163 when motor 161 is energizedand which permits the cable to unwind freely when the motor isdeenergized. Cable 163 is connected to the end of cradle 129 as at 164.In the position of the various parts shown in Figure 8, rods 139carrying collars 140 have been displaced upwardly with respect to funnel128. As pointed out cradle 129 carrying funnel 128 is free to traveltoward the left of Figure 8 which direction coincides with the directionof travel of the line of envelopes 63 carried by conveyor 29 and overwhich dispenser unit 108 is disposed. Extending from the wall ofelevator frame 91 toward which the cradle and funnel are free to travelas viewed in Figure 8 are two cams 165 each of which is positioned toengage the under surface of one of the collars 140'; the collars beingdesigned to slide along the upper surface of cams 165 so long as theyare in contact therewith. Positioned on the same wall of elevator frame91 and intermediate tubular rails 132 is an emergency switch 54 which isclosed by the end of cradle 129 just before it reaches the end of itsfree travel.

Each of the funnels is provided with a pipe 166 (Figures 8, 9) havingholes or outlets 167 and which extends around the funnel just inside thelip thereof. Pipe 166 is connected to a flexible water conduit 168 whichin turn is connected to a source of water supply through a solenoidoperated valve V1.

It is to be clearly understood that each of the dispenser units 103, 109and 110 is disposed over a line of envelopes 63 which pass thereunder asthey are carried along by the conveyor. As pointed out hereinabove, eachof the dispenser units is provided with identical parts corresponding tothose'described in detail in connection with dispenser unit 108. Thus,each dispenser unit has, for example, a corresponding set of tubularrails 132 upon which its funnel 128 is mounted free to travel from astarting position in the same direction as the conveyor carries thethree lines of envelopes 63.

The skirt 134 of yoke 129 as indicated in Figures 8 and 9 may beprovided with a pair of switches S7 and S8 so mounted as to be actuatedby a cam on crank 158, the operation of which will be more fully pointedout.

In operation a row of three envelopes 63 slowly approaches the dispensermoving from right to left (Figure 1), each of the envelopes being inline with one of the trigger bars 145. As shown in Figure 9, yoke 137 isin its normal position with set screw 147 up against stop 148. Elevator91 carrying the three dispenser units 198, 109 and 110 is in its raisedor starting position. In the schematic wiring diagram, Figure 17, thevarious switches and relays are shown as set just prior to theengagement of the trigger bars 145 by the envelopes. It is to beunderstood that the relays to be referred to are of the self-latchingtype while the timer, which may be mounted on the dispenser as indicatedin Figure 1, is of the conventional motor driven multi-contact variety.

As each of the envelopes contacts its corresponding trigger bar 145 andcontinues to be carried along by the conveyor, this motion is impartedto each of the trigger bars, thereby rods 139 carried by yokes 137 swingabout their pivots 136 (Figure 11). The yokes being pivoted, their rightends swing downward and throw switches S1. As is apparent in Figure 17one pole of each of the three switches S1 is connected in series betweencoil K1 of re ay;rRLlan dthe source of :electricalpower supply -whilegthrowing-the three switches S1, coil K-Zis deenergized while -K-l .isenergized unlatching (relay RL1 and peramitting the contacts thereof todrop down. Switch .57 .being maintained closed by the cam :on crank15,8,1the circuit is nowclosed to each-of the-drip pan motorswhich .arenow energized and ,rotate their cranks drawingthe .three'drip pans outfromunder-each of the funnelspouts 128a. After the cranks -have rotated180 switch- S7 .is allowed to open-tints stopping the motors while:switch S8 is closed by the crank completing the circuitto coil K3 ofrelay .RL2. When coil (K3 is energized relay ;RL2 Y is tmlatchedpermitting its contacts :to drop down and com- ;p1ete-t he circuit tocoilrK6-of valve V6 which when energized-connects the upperendof-cylinder 71 to the :source of air pressure. Elevator frame "9.1then starts down underithe action ;of=air piston rod 72 and controlledby the opposed hydraulic system through cam rod '85.:and ,valve 77. Asthe elevator frame starts down switches :85 and .86 are-opened. Whilethe elevator frame-continues downwardifunnel spouts 128a enter the necksof the envelopes awhjlethe -rims of theenvelope necks allow the-trigger,bars 1415 lo slide by until they abutthe under'surfaces tof .lips 146on their respective platform 1'44 and stop their further downwardmovement. Rods 139 continue downward until their collars 141 abut:platforms 5144 ,which had :been previously stopped by the envelopes andLarrest their,furthendownward:movement as well as rods 139. .As theelevator frame continues downward, rods 13,9 having ,had their downwardmovement thus arrested, ;collars-140 are-raised abovecams 1 65. Justbefore elevaplatforms close switches T82, the closing :of any one ofwhich starts the dischargecycle. 'By connecting the three switches :81in series I insure that the dispenser .will not start down untilall theenvelopes have come into precise :alinement with their ,funnel spouts.Thus, being assured .of the alinement of the-spoutsandenvelope :necks, IIconnect the three switches S2 in parallel ;so that closing :of any oneof them initiates the discharge into all three .envelopes and failure ofone or even-two f ithese'switches does not interfere with 'the formingingredients.

I "The timer is connected, as indicated in Figure 17., "to the valves:and pinch clamps of :the dispenser units 5108, '110,9,-.and 11 0 thecorresponding solenoids of the :three units being actuatedsimultaneously; :In the present in- .stance the *timerprogram may be-asfollows. Valve :Vl Opens and-closes discharging acushion of water. intoeach .of the envelopes "which Water is only ;par.t=.of the total,required. Then while -.each of the three iSfltS of pinch clamps 124,125and 126 are closed the nine solenoids 118 are actuated raising valves117 and allowingall {tubes 119 to be filled above the pinch clamps withtheir :respec- -.tive ingredients. The corresponding pinch clamps of thedispenser .units are set so as to measure equal amounts of the sameingredient. Then solenoids ;1;18.are deenergized, closing valves 117 andthe pinch clamps .124, 125, 126 are opened allowing the measuredquantities of ingredients to flow through the funnels into theenvelopes. The pinch clamps are then closed when their solenoids aredeenergized and valves V1 are-once again opened and closed deliveringthe rest of the required amounts of water. Thisfinal charge of wateralso serves to flush the tfunnels as. a result of the positioning .ofthe pipes .166 around the lips of the funnels. Just before the timerresets itself for another cycle it momentarily energizescoil K-(l ofrelay R-LZ, thecontacts of which :are shifted -to the raisedpositionwhere they are latched. With the contacts ,of relay RL2-raised,=valve V6is shifted connecting the lower end of air cylinder 71 to the source ofair pressure ,and raising the elevator frame.

dispensing of .the coating During the discharge cycle envelopes 63 havebeen :continuously moving .to theleftin Figure Bend the three :cradles.129 t with funnels 12$ therein have beenimoving in the same direction.Cams 165 are of such length that before the elevator frame starts upcollars on rods 139 have been carried over their respective cams and aremaintained raised even though platforms 144 are no longer beingsupported by the rims of their respective envelopes.

With the trigger bars 145 being thus maintained raised envelopes 63which have just received a .charge of coating forming ingredientsare'free to'be carrie'clpast thereunder. As the elevator frame reachesits fully'raised position switches S5 and S6 are closed. Since switches83 are normallyclosed the circuit is now closed to each of the funnelreturn motors 161 which now wind their cables 163 to return each of thefunnels 'to their starting positions. As each funnel reaches itsstarting position the end of its cradle opens its switch :83 thusdecnerg'izing its motor. When all of the funnels are returned all oftheswitches S3 are opened. After the funnels have started to move to theright under the influence of their cables, collars 140 are carried offof their respective cams 165 and rods 139, platforms 144 and triggerbars 145 are now 'free to dropdown into position 'to be acted upon bythe next row of envelopes. During the raising of elevator 'frame'9'1,'trigger'bars 145 were carried up out of engagement with the envelopenecks thus permitting yokes 137 to pivot and't'hrow the three switchesS1 backto the position indicated in Figure 17. When switch S6 was closedas the elevator frame reached its raised position the circuitto coil K2of relay RLl was completed, energizing the same and shifting thecontacts of this relay to the raised Position. With the contacts ofrelay RLl raised and since switch S3 has'been closed during thedischarge cycle, the circuit tothe drip pan motors 157 is completed andthe drip pans are returned to their positions underneath spouts 128a..On completion of the revolution ofcrank .158 necessary to return thedrip pans, switch S8 is opened while switch S7 is closed. The dispenseris now ready to repeat the same cycle on the arrival o'fthe next row ofenvelopes.

Switches S4 are provided as emergency raise switches in the event thetimer should fail to energize coil K4 of relay "RLZbefore any one ofcradles .129 has reached the end of its free travel along its rails. Itis apparent from Figure 1'7 that should anyone of the switches S4'beclosed, coil K4 is energized thus causing the raising of the elevatorframe irrespective of the setting of the timer and thus'avoiding damageto the apparatus or to the envelopes. Similarly, triggers 145 and yokes137 insure alinemen't of all the spouts with their envelopesbefore theelevator frame can start down. 7

After having been charged with coating forming ingredients by thedispenser, the envelopes continue tolbe carried along the path of theupper course .of the conveyor. The length of this path is such that atthe speed at which the envelopes are traveling they do not reachposition C at the end of the upper course until the coating or screenforming. particles have settled out of solution. As the envelopes arecarried beyond position C, they are gradually tilted to an invertedposition when they arrive at D. During tilting excess liquid is pouredout of the envelopes which is caught by splash guard 66 having channel66a whichleads oifthe waste liquid.

This pouroli must'be carried out very slowly, otherwise the settled;screen will slip to become uneven. It must also be carried outcontinuously, since any hesitation in the action will cause a line onthe screen where the surfaceof the pouring liquid hesitates.

To aid ,in the accomplishment of the first of these the sprocketsare-large enough to give. the desired slow speed of pour off withthebest speed oftsettling. In .the:present example this is a pitchdiameter of 39 inches. The second condition is inherent in the operationof the :rest of the ,rnachine, ;i. e., continuous motion of conveyorwith- 11 out harmful vibration or hesitation. In the present instancethe travel of the chains and hence the upper and lower courses of theconveyor may be set at four inches per minute.

Rinse and dry Next to be considered is the apparatus for setting thecoating which may include as a preliminary step the washing and rinsingof the envelope followed by drying of the coating. Referring now toFigures 13, 14 and 15, it is apparent that tube envelopes 63 are carriedinverted through the wash and rinse position 22 as well as dry position23. A substantially rectangular platform 200 has upstanding side walls201 and end walls 203, 204 forming a rectangular tank open at the top.As will be pointed out hereinafter platform 200 is vertically reciprocating in operation and therefore the tank walls are of such heightthat they do not interfere when in their top most position with thepassage of envelopes 63. Platform 200 is supported adjacent each of itscorners by four identical and parallel linkages or link systems 205,206, 207, 208 each of which comprises a long link 209 and a short link210 one-half the length of link 209. Each link 209 is pivotallyconnected as at 211 to platform 200 adjacent each corner thereof, whilethe opposite ends thereof are each pivotally connected to a slide block212 free to slide horizontally in a frame or slideway 213. The lower orleft hand ends of links 210 looking in the direction of Figure 13 arepivotally connected to fixed blocks or lugs 214 and at their oppositeends are pivotally connected to the center of the corresponding longlinks 209 as indicated at 215. The sliding blocks 212 of linkages 205and 206 are operatively interconnected by means of a rod or tie bar 216while the slide blocks of linkages 207 and 208 are connected by rod ortie bar 217. Tie bar 217 extends through a bore 218 in a bridge 219connected to or integral with a yoke 220. One end of yoke 220 is infaceto-face engagement with the sliding block of linkage 207 while theother end thereof is in engagement with the sliding block of linkage208. On one side, bridge 219 is connected to piston rod 221 and piston222 which is free to reciprocate in cylinder 223. Cylinder 223 isconnected at 224 and 225 by means of suitable pipes to a solenoidoperated valve V2 which, in turn, is connected on one side to a sourceof air pressure and on the other to an exhaust pipe. As will be morefully pointed out hereinbelow, solenoid operated valve V2 is connectedto a source of electrical power supply through switches S and S11. Forone operative position of valve V2, end 224 of cylinder 223 is connectedto the source of air pressure while the other end 225 is connected toexhaust. In the other position of valve V2, end 224 is connected toexhaust and end 225 is connected to air pressure. As is clear fromFigure 14-, tie bar 216 is also connected to yoke 220 by means of bars253 and 254. To permit fine adjustment of the rate of rise and descentof platform 200, yoke 220 is connected to piston rod 226 of piston 227free to reciprocate in cylinder 228. As schematically in dicated inFigure 14, the ends of cylinder 228 are connected through a conduit 229having an accumulator 230 in the line. Cylinder 228, conduit 229 andaccumulator 230 are filled with a suitable hydraulic fluid and the rateat which piston 227 may reciprocate is controlled by the hydraulicfluid, the passage of which, from one side of the piston to the other,is regulated by valves 231 and 232. Valves 231 and 232 are of the typewhich adjustably control the flow of hydraulic fluid in one directionwhile permitting the fluid to freely flow therethrough in the oppositedirection. Thus, the control plunger of valve 231 is conveniently placedin contact with one suitably designed cam 231a on bar 253 and controlsthe rate at which platform 200 ascends. Valve 232 is similarly locatedin connection with another cam 232a carried by bar 253 and controls therate of descent of platform 200.

On platform 200 are two rows of spouts 233 and 234. It is to beunderstood that there are as many spouts in each row as there areenvelopes 63 in each row of envelopes across the conveyor 20. Also, thespruts are so disposed that they come into registration with thelongitudinal or vertical axis of the envelopes that pass inverted overthem. The spouts are preferably mounted on flexible rubber holders 235to relieve the strain on the neck of the envelopes should one come intocontact with a spout. Thus, as indicated, there may be six such spoutsall of which are connected to a header 236 which, in turn, is connectedto a source of washing solution by means of flexible tubing 236a througha solenoid operated valve V3 which is also actuated by the closing ofswitch S10. Spouts 233 and 234 are closed at the upper ends and havedownwardly directed passages formed in their walls through which liquidis directed downwardly at the necks of envelopes 63 into which thespouts have been inserted. Concentric with the spouts and adjacent theupper ends thereof are arcuate tubes 237 which have inwardly directedperforations and which are also connected to the header 236. Thispermits simultaneous washing of the outer surfaces of the envelope neckswith the washing of the inner surfaces thereof.

Switch S10 is supported by frame 24 in such position that it is actuatedby each actuator bar 65 to bring platform 200 up and carry spouts 233 upinto the necks of one row of envelopes while spouts 234 are carried upin the necks of the preceding row of envelopes; thus, each row ofenvelopes is washed twice, once by spouts 233 and once by spouts 234.Switch S11 may be mounted on frame 24 in such position that it isactuated by trip 238 connected to end wall 203 and is closed by the trip238 as platform 200 arrives in its topmost position.

Positioned beyond wash and rinse platform 200 in the direction of travelof the lower course of conveyor 20 and to the right of platform 200 asshown in Figure 13, is an air-dry platform 239 which is supported on asystem of four parallel linkages identical in all respects with thosedescribed in connection with platform 200. Furthermore, the linkages ofplatform 239 are actuated by compressed air and controlled by ahydraulic system also identical in every respect with that shown anddescribed in connection with wash platform 200. Thus, platform 239 issupported by four linkages 305, 306, 307, 308; corresponding pairs ofwhich are interconnected by tie bars 316 and 317. Tie bar 317 extendsthrough a bore 318 in bridge 319 of yoke 320. Yoke 320 as in the case ofyoke 220, is connected on one side to a piston rod and piston 321 and322 which reciprocates in air cylinder 323. On the other side, yoke 320is connected to piston and piston rod 328, 326, which reciprocate incylinder 328. Ends 324 and 325 of cylinder 323 are connected throughvalve V5 to a source of air pressure or an exhaust line in accordancewith the setting of valve V5. The detailed construction of these variousparts will be apparent from an examination of the elevating mechanism ofplatform 200 and is, therefore, not repeated here.

Movably mounted on platform 239 and free to travel between the endsthereof is a dry rack 240 mounted on wheels 241 and which carries rowsof air spouts 242 and 243. As in the case of spouts 233 and 234, thenumber of spouts in each row 242 and 243 is the same as the number ofenvelopes in each row across conveyor 20. Furthermore, the spouts arepositioned so as to be in registration with the envelopes whichsuccessively pass over them. The air spouts may be suitablyinterconnected adjacent their lower ends by a system of conduits whichis, in turn, connected to a source of compressed air by means offlexible tubing 244 through a valve V4. Depending from the right handend or leading edge 240a of air rack 240 is a pin 245 which extendsdownwardly through an elongated longitudinal slot 246 in the floor ofplatform 239. As stated, air rack 240'is movable on platform 239 fromleft to right and back again. Positioned below platform 239 and havingits center somewhat to the right-of edge 240a of the air rack when theair rack is in its extreme left hand position is a rotatably mountedsprocket 247. A motor and sprocket 248 is disposed below platform 239and to the right of the right hand end thereof. Sprockets 247 and 248carry an endless chain 249 stretched between them. A plurality of spacedpins 250 are mounted on chain 249 and project horizontally therefrom.Sprockets 247 and 248 are so disposed with respect to slot 246 that pin245 extending v.down through slot 246 may be engaged by one of the pins250 on the upper course of chain 249 when the platform .isin its loweredposition. Motor and s;- rocket 248 drive chain 249 so that its uppercourse travels to the left in the direction of Figure 13 orcounterclockwise.

Valve 'V5 is connected to a source of electrical power supply throughswitches S12, S13, S14 and S15. Switch S12 is disposed on frame 24 so asto be closed by each moving actuator bar 65 as it passes the, same.Switch S13 which is normally closed is also supported on frame 24 and isso spaced apart from switch S12 as to be opened by one of the actuatorbars a short time intervalafter switch 812 has been closed. Switch S14is mounted adjacent the left hand end of platform 239 and is maintainedclosed so long as air rack 240 is in its starting or lefthand position.Switch S15 ismounted adjacent the other end of platform 239 and isclosed by air rack 240 as .the same approaches its terminal position.Switch S16 is mounted on platform 239 to the right of or beyond .switchS15 and acts as an emergency switch in the event .switch S15 fails tofunction properly when closed by the air rack.

Flexible air tube 244 is connected to its source of compressed airthrough solenoid actuated valve V4 which is .open when a switch S17 isclosed. Switch S17 is so dis- ,posed on the supportingframe as to beclosed by platform .239 when the platform reaches its raised position.Air rack 240 has centrally positioned on its left hand end looking inthe direction of Figure 13 a tongue 251 which ;is releasably engaged bya latch 252 disposed in alinement therewith on the left end of platform239 and which serves to releasably retain air rack 240 in its startingposition when it has been returned thereto by chain 249. Supported onthe sides of the air rack 240 are two alined elongated fingers 255 whichextend upwardly and are ofv such length as to come into engagement withthe connecting rod 54 ofv the carriage 48 which is in alinement with airspouts 242. Fingers 255 are of sufficient size :and strength as totransmit the motion of the carriage with which they are in engagement toair rack 240.

.In operation, after the envelopes have passed from C to D around theleft hand end of the conveyor and have .had excess liquid removed theyarrive at position E where the actuator bar of each row closes switch Sin passing. Switch S10 is connected to the source of current on one sideand on the other side to coil K7 of relay RL3 through a time delay relayTD. When switch S10 is closed coil K7 is momentarily energized tounlatch the relay and allow its contacts to fall and is then denergizedby the action of time delay relay TD. With the contacts of relay RL3down, coil K9 of valve V2 is energized shifting the valve so that theend 225 of cylinder 223 is connected to a source of air pressure whileend 224 thereof is open to exhaust. This drives piston 222 to the left.Piston 222 being connected through its piston rod 221, bridge 219 andyoke 220 to both tie bars 216 and 217, its motion is transmitted throughthe four parallel linkages toplatform 200 and elevates the same. Thefunction of 'time delay relay or circuit breaker TD is to insure thatcoil K7 has been deenergized before platform 200 reaches -its fullyraised position. Since the envelopes continue .in motion the wash andrinse time is relatively short. Simultaneous with the shifting of valveV2 by relay RL3, coil K11 of valve V3 is energized starting theflow ofwash ,solution through spouts 233 and 234 which are carried 41pbyplatform 200 into the necks of the overhanging:

14 envelopes. ,As platform 20!) reaches its operating .or highestposition it engages and closes switch .811 energ zing coil K8 of relay,RL3 which raises the contacts of this relay. Coil K11 of valve V3 isdeenergized while coil K10 is energized shifting valve V2 whichnowconnects the end 224 of cylinder 223 to air pressure while end 225thereof is connected to exhaust. Piston 222 is nowdriven to the rightand platform 200 is carried down to its starting position. It is to beunderstood that switch S10 is so positioned that when it is closed byone of the actuator bars, the envelopes carried by the carriage of whichsaid actuator ,bar is ,apart are. in registration Withspouts 233whilespouts 234 are the nextpreceding row- As the envelopes continue inmotion the actuator bar of their carriage next engages and closes, inpassing, switch S12. immediately after switch S12 is closed, switch S13,which is normally closed, is opened'by the actuator bar of the carriagenext preceding the one which closedswitch S12. Thus, if air rack240 isinits left ;hand or starting position .andis therefore maintainingswitch 814 closed, coil K12 is momentarily energized releasing thecontact of relay RL4and permitting them to drop out. In this position ofrelay RL4, coil K14 of valve V5 is energized shifting this valve in thesame manner coil K9 shifted valve V2. Theelevating mechanism of platform239 being identical to that of I platform 200, its operation will beunderstood from the foregoing description of the .elevationof platform260. As platform 239 reaches its operating or raised position fi-ngers255 carried by air rack 240 are interposed in front of connecting rod 540f the .carriage which closed switch S12, the motion of this carriagebeing imparted to allflaCk 240 which is free-t0 travel on platform 239in the same direction the carriage is being carried by the conveyor.Also as platform 239 reaches its operating position it closes a switchS17 energizing :the coil .of -valve V4 starting the how of dryinga'ir tospouts 242, 243. By the raising of platform .239 into operating positionspouts 242 are carried up into the :row of envelopes carried by thecarriage which closed switch S;1; 2 while gspotuts 2:43am carried upinto the next preceding row of envelopes carried .by the carriage whichopened sw-itcjh S13. ,As air rack 24.0 approaches the end of its freetravel its right hand end (Fig. 12) closes switch S15 energizing ,coilK13 and raising the contacts of .relay R14. With the contacts ofrelayRL4 raised coil K16 of valve V5 is energized shifting the valve andreversing the elevatingmechanism of the dry-platform 239 causing thesame to be lowered. As platform 239 is lowered S17 opens deenergizingthe coil of valve V4 and shutting off the flow of drying air. Whenplatform 239 is back in its starting or :fully lowered position, pin245, depending through slot 246 from the end of .air rack 240, isengaged by one of the projecting pins 250 on .chain 249. With pin 245thus engaged air rack v240 is carried back-to its starting positionwhere its left hand .end closes switch S14 and tongue 251 is-engaged byclamps 252.

.By arranging switches S12, S13 and S14 as described :hereinahove, Iavoid the possibility that the air platform will be raised except whenthe air rack 240 is in its starting position when switch S12 is firstclosed. Thus if-the .air rack is not in its starting position when S12is closed and fails to return before switch S13 is opened, a late returnof the air rack will not closethe circuit to start the dry platform up.The time interval between the closing of S12 and the opening .Of2S13 issuch if the dry plat- ;form goes up during that interval the air spoutswill 'be ,in line with the envelopes and will enter their necks. WhenS13 has been opened the envelopes have travelled so far .as to .placethem out of alinement with the air spouts. The required drying time isusually solong that in the present instance it is convenientto'accomplish the drying of two rows of envelopes simultaneously. Thedrying time may be lengthened or shortened as desired by increasing s lnber of rows o ai events an providing for .a

in registration with the envelopes o,f

correspondingly longer travel for the air rack or by decreasing thesame. The purpose of switch S14 is to prevent the closing of the circuitto valve V except when the air platform and the air rack are in theirstarting positions.

After the coatings or screens have been dried the envelopes continue tobe carried by their carriages and holders along the path described bythe lower course of conveyor 20 until they return approximately toposition A. At position A the air valves of holders 58 may be manuallyopened and the envelopes removed from the holders.

' In Figure 4, I have shown another form which the holders for theenvelopes may take. Thus, instead of endless tubing 62, I may providetwo fingers 172 mounted adjacent to the open end of a holder 173. Athird finger 174 is preferably mounted on the wall of holder 173intermediate fingers 172 and has connected to it an adjusting screw 175which is in threaded engagement with the Wall of holder 173. At itsouter end screw 175 carries a thumb piece 176 by means of which finger174 may be readily adjusted. When this type of holder is used it ismounted on carriages as hereinbefore described with respect to holders58. With adjusting screw 175 unscrewed or turned out somewhat, anenvelope may be inserted into holder 173. Then the adjusting screw isturned in until all of the fingers 172 and 174 are snug against the sideof the envelope. In view of the somewhat conic outline of such objectsthe base thereof is of larger diameter than the point around which thefingers are disposed and they therefore prevent the envelope fromslipping out of the holders even when it. is tilted -or inverted. Screw175 need only be tightened sufficicntly to remove free play from theenvelope with respect to the holder and should not be so tightened as todamage the object.

Instead of guide plates 4d (Figs. 1 and 2) having guide 42 I may provideguides in the form of flexible belts or straps 170 (Figure 5) at each ofthe four corners of conveyor 20. Such guide belts 170 may be connectedat their ends to a suitable bracket on the conveyor frame throughsutficiently strong biasing means such as coil springs 171. When suchguides are utilized, upper rails 47 are provided with arcuate extensions47a which terminate above the lower rails and spaced therefrom by adistance equivalent to the outside diameter of rolls 51,

-52 of carriages 48. Those carriages which are passing around the endsof the conveyor rails are maintained thereon by the action of guidebelts 170 on guide rolls 57, one of which projects outwardly from eachof the two trucks 50 of carriages 48, the guide belt being positionedadjacent the rails for this purpose.

While I have indicated the preferred embodiments of my invention ofwhich I am now aware and have also indicated only one specificapplication for which my invention may be employed, it will be apparentthat my invention is by no means limited to the exact forms illustratedor the use indicated, but that many variations may be made in theparticular structure used and the purpose for which it is employedwithout departing from the scope of my invention as set forth in theappended claims.

I claim:

1. Apparatus for drying inside surfaces of a hollow object comprisingcarrier means adapted to carry said object, means for moving saidcarrier means in one direction along a predetermined path, drying meansadjacent said path and including a platform movable angularly towardssaid path and a carriage carrying an air nozzle movable on said platformin a path substantially parallel to said path, means actuated by saidcarrier means for moving said platform and carriage towards said pathinto operative position for extending said air nozzle into said object,means responsive to the movement of said platform for connecting saidair nozzle to a source of air under pressure, a finger on said carriageengaging said carrier means when said carriage is moved to saidoperative'position for moving said carriage in said parallel path, meansat one end of said parallel path actuated by said carriage for movingsaid platform and carriage away fromsaid carrier means and for removingsaid air nozzle from said object, and means for moving said carriage tothe other end of said parallel path.

2. In an automatic apparatus for applying coatings to a surface of anobject, carrier means adapted to carry said object, means for movingsaid carrier means in one direction along a predetermined path, settingmeans adjacent to said path and including a platform movablesuccessively toward and away from said path during movement of saidcarrier means, and a carriage movable on said platform in a pathsubstantially parallel to said first named path only, means actuated bysaid carrier means and engaging only said platform for moving saidplatform and said carriage toward said path and into operative position,a finger on said carriage engaging said carrier means in said operativeposition, whereby said carriage is moved on said platform in saidsubstantially parallel path, means on said platform and in said lastnamed path actuated by said carriage when said carriage is at the end ofsaid last named path for moving said platform and carriage away fromsaid operative position, a power transfer means below said carriage, anda second finger on said carriage engaging said power transfer means atthe terminal portionof the last named movement of the platform.

3. In an automatic apparatus for applying coatings to a surface of anobject, carrier means adapted to carry said object, means for movingsaid carrier means in one direction along a first path, setting meansadjacent to said first path and including a platform, supports for saidplatform, said supports restraining movement of said platform out ofparallel relation to said first path and a carriage movable on saidplatform only, in a second path parallel to said first path, a firstmeans adjacent to said supports for moving said carriage to a firstterminal position on said platform, a second means connected to saidsupports for moving said platform toward said first path and to disposesaid carriage in operative position with respect to said object and toengage said carrier means, whereby said carriage travels with saidobject in said second path to a second terminal position on saidplatform, means intermediate said first and said second terminalpositions, engaged by said carriage during said travel thereof foractuating said power means for moving said platform away from said firstpath and disengaging said carriage from said carrier means, andactuating means at said second terminal position and responsive to themovement of said carriage for actuating said first means for moving, forreturning said carriage to said first terminal position.

4. In an automatic apparatus for applying a coating to a surface of anobject, carrier means adapted to carry said object, means for movingsaid carrier means in one direction in a first path, setting meansdisposed adjacent to said path, said setting means including anelongated platform, movable supports engaging said platform forsupporting said platform in parallel relation only, to said first path,means engaging said supports for moving said platform toward said path,a carriage movable along said platform and having a finger engaging saidcarrier means when said platform is moved toward said path, whereby saidcarriage moves along said platform with said carrier means, saidcarriage having a nozzle engaging said object when said carriage engagessaid carrier means, and means on said platform engaged by said carriageduring a' terminal movement thereof on said platform for actuating saidmeans for moving, whereby said platform and carriage are moved away fromsaid pathand said carriage becomes disengaged from said carrier means.

5. In an automatic apparatus for applying a coating to a surface of anobject, carrier means movable in 'a first path and adapted to carry saidobject in said path, a first means for moving said carrier means in saidfirst path, a movable platform positioned adjacent to said first pathand extending parallel thereto, said platform having an elongatedsurface facing said first path and defining a second path, a carriageengaging said surface, a second means for moving said carriage from oneend to the other of said second path, a first actuating means at saidone end adapted to be engaged by said carriage at said one end foractuating said second means for moving, for moving said carriage to saidother end of the second path, a third means for moving said platform ina third path, toward said first path and into operative position whilepreserving the parallel relation between said elongated surface and saidfirst path, a second actuating means in said first path for actuatingsaid third means for moving, to move said platform to said operativeposition, said carriage having a finger engaging said carrier means anda nozzle engaging said object when said platform is in said operativeposition, whereby said carriage moves on said elongated means with saidcarrier means and object, for coating said surface of said object, and athird actuating means in the path of move ment of said carriage on saidelongated surface for actuating said third means for moving forreturning said platform to its initial position and disengaging saidcarriage from said carrier means and said object.

6. In an automatic apparatus for applying coatings to surfaces ofobjects, carrier means adapted to carry said objects, means for movingsaid carrier means in one direction along a first predetermined path ata substantially constant speed, setting means adjacent to said firstpath, said setting means including a first means movable successively toand away from said first path, said first means having a surface facingsaid first path and preserved in parallel relation to said first pathduring movement of said first means, a second means movable only on saidsurface in a second path parallel to said first path, said second meanshaving an element engaging said carrier means, and a nozzle adapted toengage one of said objects when said first means is moved toward saidcarrier, whereby said second means is caused to move in said second pathin said one direction on said surface and said nozzle follows the travelof said one of said objects on said carrier means for a settingoperation, means for moving said first movable means, actuating means insaid first path for actuating said last named means for moving, formoving said first means toward said first path, and actuating means insaid second path for actuating said last named means for moving, formoving said first movable means away from said first path on completionof said setting operation.

7. In an automatic apparatus for applying a coating to a surface of amoving object, an elongated platform movable toward and away from thepath of movement of said object, support means engaging said platformfor preserving said platform in parallel relation to said path duringmovement of said platform, a carriage movable along said platform, afirst means for moving said platform successively toward said path andinto operative position whereby said carriage engages said object, andaway from said path and position whereby said carriage is disengagedfrom said object, a. second means for moving said carriage, whereby saidcarriage is moved along said platform from a starting from a startingposition adjacent to one end of said platformrwhile engaging saidobject, a switching element in the path of movement of said carriage onsaid platform and adjacent to the other end of said platform, wherebysaid element is actuated by said carriage, said switching element beingadapted to actuate said first means for moving, for retracting saidplatform from said operative position, whereby said carriage is moved ina predetermined path and is disengaged from said object, and a thirdmeans for moving said carriage to said starting position, said thirdmeans for moving being disposed in said predetermined path, saidcarriage having a finger engaging said third means for moving when saidcarriage is adjacent to a terminal position in said predetermined path,whereby said carriage is moved to said starting position.

8. In an automatic apparatus for applying a coating to a surface of amoving hollow object having an opening, carrier means movable in ahorizontal path, a first means for moving said carrier means in onedirection, setting means positioned below said path, said carrier meansbeing adapted to support said object with said opening extendingdownwardly, said setting means including an elongated platform extendingparallel to said path and a carriage movable along said platform andhaving an upwardly extending nozzle and finger, a second means formoving said platform upwardly toward said path, a first actuating meansin said path and adapted to be tripped by said carrier means foractuating said second means for moving, whereby said platform, carriagenozzle and finger are moved upwardly and said nozzle enters said openingand said finger engages said carrier means for a setting operation andsaid carriage is caused to travel from a starting position on saidplatform in said direction by engagement between said finger and carriermeans, two actauting elements spaced along said platform for successiveengagement by said carriage, the first of said elements being connectedto said second means for moving, whereby said platform is lowered andsaid nozzle is disengaged from said object when said first of saidelements is engaged by said carriage, and a third means for moving inthe downward path of said carriage and connected to the second of saidactuating elements for moving said carriage in a direction opposite tosaid first direction, whereby said carirage is returned to said initialposition.

References Cited in the file of this patent UNITED STATES PATENTS1,445,359 Scarborough et al. Feb. 13, 1923 2,547,884 Paasche Apr. 3,1951 2,561,629 Moore et al. July 24, 1951 2,589,088 Johnson Mar. 11,1952 2,646,773 Burton July 28, 1953

